The goal is to peek interest, hold it, then send it HOME!
A rule of thumb for a PDF or physical portfolio is about 12 pieces. You want to show diversity in your work as well, so curating your pieces can often be a challenge. You should also have different portfolios for different audiences. Pieces can overlap, but you want to make sure you are speaking to your audience. After all, as a creative, that is our job. If not our job, sending a message is still the point of your creation, isn't it?
You want to start strong. Begin with a few of your best pieces. Fill the middle with ones that are more audience-specific (I literally got a job JUST from 2 editorial pieces I included among other agency work I had done). End with some more great pieces to "send it home". Also pay attention to the job listing. There may be some other instructions embedded in the post. I went on an interview where the interviewer said they received 100s of applications, but were only interviewing 5 people because we were the only ones that included "what is your dream vacation" — which was something they asked for - clear as day - in the posting. 5 people! out if hundreds of applicants! that followed their directions....
Sometimes the PACKAGE matters. Again, read the posting! If it is something local, you might want to create an interesting package for your printed portfolio. This request is less and less for sure, but you never know! It may be the reason you get an interview - or better yet - THE JOB! You have to stand out from every other designer or artist looking to get that position. (Print Magazine usually has some GREAT posts, or just Google portfolio ideas, etc...) I did win a silver ADDY Award for my RFP package for an agency I freelanced at. It was for a local "fancy" college so I created a graduation cap by hand that housed all the RFP information.
Your online portfolio is a different ballgame. It is really the place to shine! And your audience could literally be anyone! But don't go too overboard! Maybe classify pieces by category as an option (ie, logos, large format, digital, illustrations, and so on). There are so many things we do as creatives. We want to show it all, but we also don't want to vomit the work all over a viewer either, right? Nobody likes to be vomited on. Gross. LOL! But pick your best and show your breadth.
Don't forget about social media either! People like doing business with people they know. By creating a persona - or just be yourself - on your SM sites, you are building a visual relationship with viewers. (Hello!!! Leslie Allan Jordan over the pandemic lock down!) You don't have to be all "out there," airing your dirty laundry or anything like that, but giving peeks into your personal life will work. You do not need to share intimate details! Like at all. Say you go on vacation - post a sunset pic and a snappy headline. You end up having to go old school and make something by hand - show the progress, or even the mess and include catchy and common hashtags! You see a cool logo or a funny advertisement or an amazingly gorgeous flower - snap a pic and post it! Give props to the artist if you can find out (often it is impossible), but include hashtags. Your freeloading live-in roommate (aka your pet) strikes a cute or funny pose - post that! A really good friend of mine does code and literally one of his major name clients (a major streaming channel but not Netflix) commented positively on their posting heavy and trash metal band album covers saying something along the line of liking to work with people who know how to destress in a positive way - blaring some good old fashioned metal! He is just being himself!
We got into these creative jobs because it was fun, right? We also tend to be pretty good at that job, so HAVE FUN! We, for sure, can market ourselves, right???